Transcript Multiple Alleles and

MULTIPLE ALLELES
AND
Human Blood Types
MANY HUMAN TRAITS ARE CONTROLLED
BY A SINGLE GENE WITH JUST TWO
ALLELES
EX: WIDOW’S PEAK, HAIR ON FINGERS,
DIMPLES, CLEFT CHIN, EAR LOBES
FRECKLES
MULTIPLE ALLELES
• Some human traits are controlled by
multiple alleles
• Even though there are more than two
alleles for the trait, a person can only have
two alleles for the trait
BLOOD
TYPE
•The 4 human
blood types are:
The alleles for
blood type are
•A, B. AB & O
A, B, & O
BLOOD TYPE ALLELES
•A-Dominant to O, Codominant to B
•B-Dominant to O, Codominant to A
•O-Recessive to both A & B
GENOTYPE
PHENOTYPE
AA, AO
TYPE A
BB, BO
TYPE B
AB
TYPE AB
OO
TYPE O
PROBLEMS
IN THE MATERNITY WARD, MRS. BRIGHT AND MRS.
LIGHT SHARED A ROOM. WHEN THEY WERE
READY TO GO HOME, MRS. BRIGHT INSISTED THAT
SHE HAD BEEN GIVEN THE WRONG BABY. THE
BABIES LOOKED VERY MUCH ALIKE, AND
UNFORTUNATELY, NO ONE COULD FIND A RECORD
OF THE BABIES’ FOOTPRINTS. HOSPITAL
OFFICIALS TOLD MRS. BRIGHT SHE WAS MISTAKEN
AND SENT HER AND THE BABY HOME. MRS.
BRIGHT EVENTUALLY ASKED THE HOSPITAL TO
PERFORM IDENTIFICATION TESTS. SEVERAL
WEEKS LATER, BLOOD TESTS SHOWED THE
FOLLOWING DATA.
MRS. BRIGHT-TYPE AB
MR. BRIGHT-TYPE O
BABY AT BRIGHT’S HOME-TYPE O
MRS. LIGHT-TYPE A
MR. LIGHT-TYPE A
BABY AT LIGHT’S HOME-TYPE A
WERE THE BABIES
“SWITCHED AT
BIRTH” ?
SUPPOSE A FATHER OF BLOOD TYPE B AND A
MOTHER OF BLOOD TYPE O HAVE A CHILD OF
TYPE O. WHAT ARE THE CHANCES THAT THEIR
NEXT CHILD WILL BE BLOOD TYPE O? TYPE B?
TYPE A? TYPE AB?
A WOMAN WHO HAS TYPE A BLOOD HAS A CHILD
WITH TYPE AB BLOOD. SHE IS SUING A MAN FOR
CHILD SUPPORT WHO HAS TYPE O BLOOD. IS SHE
SUING THE RIGHT MAN?
CAN BLOOD TYPE PROVE
PATERNITY?
WHAT CAN IT PROVE?